Yarn apparatus



May 29, 1956 w. T. R. KINRAIDE YARN APPARATUS 2 Sheets-Sheet 1 Filed July 12, 1950 INVENTOR.

WILLIAM T. R. KINRAIDE A T TORNE Y y 9, 1956 w. T. R. KINRAIDE 7 2,747,251

YARN APPARATUS Filed July 12, 1950 2 Sheets-Sheet 2 INVENTOR WILLIAM T. R. KINRAIDE BY (01- WJM ATTORNEY YARN APPARATUS William Thomas Reed Kiuraide, Bolton, Mass., assignor to E. I. du Pont de Nemours and Company, Wilmington, DelL, a corporation of Delaware Application July 12, 1950, Serial No. 173,395

7 Claims. (Cl. 2835) This invention relates to improvements in apparatus and methods for handling a running length of yarn, particularly in warp form. It relates in particular to a means for applying an equal and uniform tension on a plurality of running lengths of yarn. Still further the means will automatically remove a broken end of yarn from the path of the running warp. V

In the manufacture of high tenacity synthetic yarns, it is customary to orient the polymer molecules by means of a drawing process. The drawing is usually conducted in one or more stages between rolls operating at progressively increasing peripheral speeds. After leaving the high speed draw rolls the yarn may be given further treatment on-the-run or may be wound onto a suitable package.

The preferred process involves applying all the desired after-treatments to the yarn on-the-run and winding the yarn on a final package for sale. From the standpoint of economy and uniformity of treatment, it is preferred to apply the after-treatments to improve the properties of synthetic yarns to a plurality of strands of yarn simultaneously. This is generally done in warp form with the individual strands of yarn running in close parallel relation to one another.

After processing a synthetic yarn, it is generally wound upon some package, such as a bobbin or pirn, under tension. Most of this tension is usually applied as the yarn leaves the final roll by means of a cot, a rubber covered or cork roll which rests by gravity on the final roll and is surface driven by contact with the driven roll. The yarn leaves the final roll at the nip between the roll and the cot and is tensioned by the pressure of the cot on the roll. In many cases in the processing of synthetic yarns, the final roll operates at high speeds. With a cot, even with a cork or rubber surface, considerable bouncing occurs at these speeds. This results from unbalance or runout of the contacting rolls and the high forces generated under these conditions. The bouncing causes crushing damage to the yarn and non-uniformities in winding tension which can easily show up later as nonuniformities in dyed fabric.

When handling a plurality of strands of yarn on close centers, as in a warp, a broken strand causes much trouble. With the tension on the strand relieved by the break, the strand forms a Wrap on one of the processing rolls. In any case, it will foul the adjacent strands and cause considerable loss in time in shutdown. A cot will not prevent a roll wrap, and a roll wrap under a cot merely accentuates the difficulties cited above.

Accordingly, it is an object of this invention to provide a process and an apparatus for handling a plurality of strands of yarn under tension, as in a warp. It is a particular object to provide means for applying a uniform snubbing tension simultaneously to the individual strands of yarn in a warp as they leave a high speed processing roll. It is a further object to provide said tensioning means such that it prevents roll wraps. It is still a further object to provide a tensioning means for handling a warp of yarn which acts in combination with a yarn waste nited States Patent "ice removal device to prevent a broken strand of yarn from fouling adjacent strands. Other objects will become apparent from the description which follows.

The objects of this invention are accomplished by the provision of an endless belt in short contact with the surface of a driven roll, the belt being driven at essentially the same surface speed as the roll. The traveling belt is preferably positioned to contact a surface of the roll just prior to the point where the yarn leaves the roll. With the belt placed in this position, a strand of yarn that breaks after it leaves the roll is thrown by the belt out of the plane of the warp and into the grasp of a waste collecting device properly positioned with respect to the belt and roll. The contact of the belt with the roll is made as short as possible. At the contact the belt is bent around the roll for a short arc. The deflection of the belt is at an angle of about 0.5 to about l.0 from a straight line tangent both in the approach and departure of said belt to said roll. This angle is designated as in Figure 3, the line tangent being AB; the normal path of the belt would be that given by dotted line CD which line is parallel to AB. The warp is directed into the resultant nip so that the yarn ends do not contact the belt prior to contacting the roll. Also the yarn ends are directed from the nip so that they leave the belt, prior to leaving the roll. Due to the belt thickness and the slight bend at the contact the surface speed of the belt at the point of contactis not thesame as at other points. To minimize yarn damage the warp is made to touch the belt only in that area that contacts the roll.

The waste collecting device, usually a suction waste nozzle, is placed far enough away from the normal yarn path so that it does not pick up running ends but only broken ends. In stringing up a running end the yarn is usually out between the string-up device and the pirn after it has been started on the pirn. This results in a momentary slack and the waste collector should be far enough away so that it does not interfere with the re-tensioning. Usually the collection device is placed at least 2 inches away from the warp. The angle of the belt is set to throw broken ends into the mouth of the waste collector which thus picks these ends up automatically. For convenience, the broken end is thrown in an upward direction away from the warp below.

The invention is described further below and is shown in the figures of which Figure l is a plan view of the apparatus shown in Figure 2.

Figure 2'is a side elevation; and

Figure 3 is an enlarged view of the relation of the bel and driven roll to illustrate the belt deflection.

Referring to Figure 2, the yarn warp 1 passes over roll 10 and under roll 11 and through the nip formed by the driven roll 2 and the belt 3 and on to winding devices not shown. The yarn tensioning device of this invention comprises the driven roll 2 in contact with the traveling endless belt 3 positioned between rotating supports 4 and 5 The traveling belt 3 is driven by roll 5 at essentially the same surface speed as the driven roll 2. The roll 4 is an idler roll supported and positioned by arm 13 by means of the pivot 14 and set screw 15. The tension on the traveling belt 3 is determined by the position of the idler roll 4. The yarn tensioning device comprising the driven roll 2 and belt 3 is made to handle the warp of yarn at the proper speeds by synchronizing their drive with that of the final processing roll 11. The synchronization is accomplished in part by means of chain 6 which is positively driven by the drive of roll 11 and by the driven toothed wheel 8. The toothed wheel 7 is in fixed position and serves as a means of synchronizing the takeup device and the belt snubber through a special generator device. Another idler wheel 9 is part of an automatic tensioner for taking up slack in the chain. A suction nozzle 12 is positioned near the belt 3 and out of the path of the warp of yarn leaving the tensioning device.

The snubbing tension, or the ability of the belt snubber of this invention to pull or feed yarn, depends on the area of contact with the yarn and the friction. The friction is a function of the pressure on the yarn and the surface characteristics of the yarn, belt, and roll. The pressure on the yarn is determined by the tension on the belt 3 and the deflection of the belt by roll 2. The actual contact between the yarn and the belt should be as short as practicable to prevent damage to the yarn. Accordingly, since the surface characteristics are relatively constant, the tension on the yarn warp is preferably varied by changing the tension on the belt 3 by means of the arm 13, pivot 14 and set screw 15. Both the belt and the driven roll 2 must operate at essentially the same speed to forward the yarn with as little rubbing action as possible. The belt is of any pliable material such as rubber, cotton, coated fabrics, etc. For example, a four-ply cotton belt of medium weight and inch thickness has been employed successfully for long periods of time.

The tendency for wraps to form on the roll 2 and belt 3 should be relatively the same and low. The driven roll 2 preferably has a matte surface which minimizes the tendency for wraps to form on this roll. When a break in one of the strands of yarn occurs beyond the nip of roll 2 with the belt 3, the belt throws the loose end of yarn into the mouth of the suction nozzle waste collector 12. The suction nozzle picks up the running end of yarn and continuously removes the Waste until the operator can pick it up and string it up again. In this way the running end of yarn going to waste is maintained under the proper tension and yet it will not foul adjacent strands of yarn. The restringing-up of an end of yarn running into the Waste nozzle 12 is best accomplished by using a stringingup aspirator. The waste collector may be any standard device, such as nip rolls, although the suction device shown in the diagram is preferred.

The cooperation of the belt snubber with the waste collector to automatically handle a broken end of yarn is a particular feature of this invention, for most of the breaks occur between roll 2 and the wind-up device. The combination of the belt 3 and roll 2 traveling at essentially the same surface speeds serves a dual purpose when used in cooperation with a properly positioned waste collector.

In addition to the application of the belt snubber of this invention to the handling of a plurality of running lengths of yarn in warp form, the belt snubber also finds utility in delivering yarn, particularly heavy staple tows to a collection can.

Any departure from the above description which conforms to the present invention is intended to be included within the scope of the claims.

I claim:

1. Apparatus for uniformly tensioning yarn ends in a warp which comprises a driven roll; an endless belt driven at essentially the speed of said driven roll and located to form a slight nip with said driven roll through which nip said warp runs, said belt located at an angle to said warp to deflect any broken end out of the plane of said warp; a collecting device to receive said broken end; and means to adjust the pressure of said belt against said driven roll.

2. Apparatus in accordance with claim 1 in which said belt is deflected at the said nip at an angle of about 0.5 to about l.0 from the straight line tangent to the approach and departure of said belt to said roll.

3. A process for uniformly tensioning a yarn end which comprises contacting the surface of an endless belt with a roll to deflect said belt, the said contact bending said belt around said roll for a short are to form' a short nip; driving said belt and said roll at essentially the same peripheral speeds at the points of contact at said nip; and feeding said end to and from said nip so that said end does not contact said belt prior to contacting said roll and contacts said belt only at said nip.

4. A process for uniformly tensioning yarn ends in a warp which comprises contacting the surface of an endless belt with a roll to deflect said belt, the said contact bending said belt around said roll for a 'short contact to form a short nip; driving said belt and said roll at essentially the same peripheral speeds at the points of contact at said nip; and feeding said Warp to and from said nip so that said warp does not contact the said belt prior to contacting said roll and contacts said belt only at said nip, said belt being located at an angle to said warp to deflect any broken end out of the plane of said warp.

5. A process in accordance with claim 4 wherein said broken end is thrown upward out of the plane of said warp and is continuously removed until restringing-up.

6. Apparatus for uniformly tensioning yarn ends which comprises an endless belt and a roll, said roll being located to deflect said belt from its normal path by contacting said belt to bend it around said roll for a short arc to form a short nip; means for driving said belt and said roll at essentially the same peripheral speeds at the points of contact of said nip, and means for feeding said ends to and from said nip so that said ends do not contact said belt prior to contacting said roll and contact said belt only at said nip, said belt being located at an angle to said ends to deflect any broken end out of its normal path from said roll.

7. Apparatus in accordance with claim 6 which includes a collecting device to receive said broken end.

References Cited in the file of this patent UNITED STATES PATENTS 236,068 Newcomb Dec. 28, 1880 1,439,331 Schofield Dec. 19, 1922 2,132,789 Inglis Oct. 11, 1938 2,441,189 Eshleman May 11, 1948 2,522,250 Bechtler Sept. 12, 1950 2,621,390 Nield Dec. 16, 1952 FOREIGN PATENTS 45,410 Netherlands May 16, 1939 65,054 Denmark Nov. 11, 1946 614,031 Great Britain Dec. 8, 1948 

1. APPARATUS FOR UNIFORMLY TENSIONING YARN ENDS IN A WARP WHICH COMPRISES A DRIVEN ROLL; AN ENDLESS BELT DRIVEN AT ESSENTIALLY THE SPEED OF SAID DRIVEN ROLL AND LOCATED TO FORM A SLIGHT NIP WITH SAID DRIVEN ROLL THROUGH WHICH NIP SAID WARP RUNS, SAID BELT LOCATED AT AN ANGLE TO SAID WARP TO DEFLECT ANY BROKEN END OUT OF THE PLANE OF SAID WARP; A COLLECTING DEVICE TO RECEIVE SAID BROKEN END; AND MEANS TO ADJUST THE PRESSURE OF SAID BELT AGAINST SAID DRIVEN ROLL. 